In order to protect the main objective of a surgical microscope from contamination during an operation, it is possible to arrange a protection glass module in front of the main objective. The protection glass module includes a protection glass adapter and an objective protection glass. The protection glass adapter is connected mechanically to the surgical microscope. The objective protection glass is arranged on the protection glass adapter, such that an operating site can be viewed through the main objective and the objective protection glass. In addition, the protection glass adapter can be connected to a sterile cover film in order to protect the entire surgical microscope from contamination during an operation.
DE 10 2007 043 995 A1 discloses a protection glass adapter, designated there as a mountable protection glass frame, for a surgical microscope. During the mounting of the protection glass frame, lateral guide tabs ensure guiding contact with the surgical microscope. Thereafter, latching pins engage in receiving bores, and a lug engages in the recesses provided for it. The exact positioning of the protection glass frame is obtained when resilient pressure pins, which are mounted in the receiving bores perpendicularly with respect to the mounting direction, latch into the respective narrowed zone of the latching pins.
When this protection glass frame is mounted, there is a relatively large contact surface and, by association, relatively great friction between surgical microscope and protection glass adapter. When the latching pins engage in the receiving bores and resilient pressure pins are moved counter to the spring force, the force that has to be applied to be able to arrange the protection glass adapter on the surgical microscope increases. These forces may mean that the surgical microscope has to be held in order to ensure that its position does not change during the mounting of the protection glass adapter.